Textile webs in general are subject to curling along an edge or selvage thereof while being handled in open width and often develop curls, pressed folds or creases therealong due to improper handling, web tension, or the like. Knit or other flimsy textile webs in particular, when processed or handled at low tension or generally tensionless conditions tend to curl or roll up along the selvage. In order to produce a good quality roll of a textile web, or to achieve proper web handling along a process line for printing, inspection, drying, extraction of moisture, washing, doubling, tacking or other web treatment, it is most desirable, if not necessary, to ensure that the web is maintained in a flat condition where little or no fabric deformation is present at either selvage during winding or processing as set forth above. Proper package preparation or web handling may thus be achieved in conjunction with apparatus of the present invention that engages the web selvage and due to a particular action, removes curl, folds and creases from the selvage of the web. While the device of the present invention is suitable for curl, fold and crease removal, hereinafter, decurling is intended to refer to all.
Several different classes of decurling devices have heretofore been developed that include static as well as power driven approaches. Among the power approaches to decurling, exemplary of same are a driven type where oppositely opposed discs, rotating fingers, screws, belts or the like are located along a selvage of the web. The elements are driven to produce a motion which, in turn, imparts a spreading effect to the web to remove the curl. Likewise, fluid jets have been directed against the web curl to apply a decurling or uncurling force thereon. The power driven approach to decurling of necessity, requires a motive force for driving the particular decurling elements. Such obviously adds to cost of operation and likewise, leads to the necessity for continuing maintenance and replacement of parts, not to mention a significant initial capital cost.
The improved decurling device of the present invention is a static type structure. Known static systems include principally the decurler described in U.S. Pat. No. 4,217,682 to Young et al over which the present invention represents improvement. The Young et al web edge decurler has been commercially successful and performs the decurling operation in a very suitable fashion. Likewise a similar static structure utilizes fins that are secured to opposed plates, with the fins defining helices along the length of same, or starting at a flat flange and turning to a generally vertical fin for the effective length of the structure, and a web passageway is defined between the fins for removing curl, etc. from a moving web. Other known static systems include a pair of spring loaded elements that are disposed above and below the web, with each of the elements being U-shaped where a short leg of the U is presented on the web side and engages the web to strip curl therefrom. Still further, another known static structure includes a planar surface having ridges disposed thereon over which the web passes, with frictional forces produced between the web and the ridges to remove curl from the selvage of the web. Other decurling devices are disclosed in British Pat. No. 105,895 to Canby et al, British Pat. No. 117,427 to Greenwood, and German Pat. No. 276,759 to Spuhr.
Decurling devices according to teachings of the present invention represent a definite technological advance in the art which is not believed to be taught or suggesed by any of the prior art set forth above, or by any other known prior art.